Method and device for performing communication on basis of power saving mode

ABSTRACT

Provided are a method for performing wireless communication by a first device, and a device supporting same. The method may comprise the steps of: establishing a radio resource control (RRC) connection with a base station; establishing a PC5 connection with a second device that relays communication between the first device and the base station; setting, on the basis of establishment of the PC5 connection with the second device, a power saving mode for saving power related to Uu communication between the base station and the first device: and performing communication with the base station on the basis of the power saving mode.

TECHNICAL FIELD

This disclosure relates to a wireless communication system.

BACKGROUND

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic. Vehicle-to-everything (V2X) refers to a communicationtechnology through which a vehicle exchanges information with anothervehicle, a pedestrian, an object having an infrastructure (or infra)established therein, and so on. The V2X may be divided into 4 types,such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

SUMMARY

Meanwhile, a remote UE which is linked with a relay UE and in anRRC_CONNECTED state with a base station may transmit/receive datato/from the base station through the relay UE. In this case, a problemof how to handle an unused Uu link of the remote UE may occur. If theremote UE does not perform monitoring the Uu link in consideration ofpower saving, the remote UE can obtain a gain for power saving, but alatency may occur when switching from the PC5 link to the Uu link. Dueto the latency, service continuity performance may deteriorate.

In one embodiment, provided is a method for performing wirelesscommunication by a first device. The method may comprise: establishing aradio resource control (RRC) connection with a base station;establishing a PC5 connection with a second device relayingcommunication between the first device and the base station; configuringa power saving mode for saving power related to Uu communication betweenthe base station and the first device, based on the establishment of thePC5 connection with the second device; and performing communication withthe base station based on the power saving mode.

In one embodiment, provided is a first device adapted to performwireless communication . The first device may comprise: one or morememories storing instructions; one or more transceivers; and one or moreprocessors connected to the one or more memories and the one or moretransceivers. The one or more processors may execute the instructionsto: establish a radio resource control (RRC) connection with a basestation; establish a PC5 connection with a second device relayingcommunication between the first device and the base station; configure apower saving mode for saving power related to Uu communication betweenthe base station and the first device, based on the establishment of thePC5 connection with the second device; and perform communication withthe base station based on the power saving mode.

The UE can efficiently save power related to Uu communication.

DETAILED DESCRIPTION

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure.

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 6 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 9 shows an example of a relay scenario, based on an embodiment ofthe present disclosure.

FIG. 10 shows a procedure for a remote UE to operate in a power savingmode, based on an embodiment of the present disclosure.

FIG. 11 shows a method for a remote UE to perform communication based ona plurality of relay UEs, based on an embodiment of the presentdisclosure.

FIG. 12 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure.

FIG. 13 shows a method for performing wireless communication by a basestation, based on an embodiment of the present disclosure.

FIG. 14 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 15 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 16 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 17 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 18 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 19 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B. C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example. “A, B, C” may mean“A. B. or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control infomiation”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-20(X). The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi). IEEE 802.16 (WiMAX). IEEE 802.20. evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 2 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer exchanges an RRC message betweenthe UE and the BS.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 3 may be combined withvarious embodiments of the present disclosure. Specifically, (a) of FIG.3 shows a radio protocol stack of a user plane for Uu communication, and(b) of FIG. 3 shows a radio protocol stack of a control plane for Uucommunication . (c) of FIG. 3 shows a radio protocol stack of a userplane for SL communication, and (d) of FIG. 3 shows a radio protocolstack of a control plane for SL communication.

Referring to FIG. 3 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medi um access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., a MAC layer, an RLC layer, a packetdata convergence protocol (PDCP) layer, and a service data adaptationprotocol (SDAP) layer) for data delivery between the UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.

Referring to FIG. 4 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)). a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15^(∗)2^(u)) N^(slots) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u=0) 14 10 1 30 KHz (u=1) 14 20 2 60 KHz(u=2) 14 40 4 120 KHz (u=3) 14 80 8 240 KHz (u=4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15^(∗)2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u=2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 450 MHz - 6000 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4. FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 410 MHz - 7125 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 5 may becombined with various embodiments of the present disclosure.

Referring to FIG. 5 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP. one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS. CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel state information -reference signal (CSI-RS) (excluding RRM) outside the active DL BWP. Forexample, the UE may not trigger a channel state information (CSI) reportfor the inactive DL BWP. For example, the UE may not transmit physicaluplink control channel (PUCCH) or physical uplink shared channel (PUSCH)outside an active UL BWP. For example, in a downlink case, the initialBWP may be given as a consecutive RB set for a remaining minimum systeminformation (RMSI) control resource set (CORESET) (configured byphysical broadcast channel (PBCH)). For example, in an uplink case, theinitial BWP may be given by system information block (SIB) for a randomaccess procedure. For example, the default BWP may be configured by ahigher layer. For example, an initial value of the default BWP may be aninitial DL BWP. For energy saving, if the UE fails to detect downlinkcontrol information (DCI) during a specific period, the UE may switchthe active BWP of the UE to the default BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. For example, the UE may receive a configuration for theUu BWP from the BS/network. The SL BWP may be (pre-)configured in acarrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE.For the UE in the RRC CONNECTED mode, at least one SL BWP may beactivated in the carrier.

FIG. 6 shows an example of a BWP. based on an embodiment of the presentdisclosure. The embodiment of FIG. 6 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 6 that the number of BWPs is 3.

Referring to FIG. 6 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

A sidelink synchronization signal (SLSS) may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS), as an SL-specific sequence. The PSSS may be referred toas a sidelink primary synchronization signal (S-PSS), and the SSSS maybe referred to as a sidelink secondary synchronization signal (S-SSS).For example, length-127 M-sequences may be used for the S-PSS, andlength-127 gold sequences may be used for the S-SSS. For example, a UEmay use the S-PSS for initial signal detection and for synchronizationacquisition. For example, the UE may use the S-PSS and the S-SSS foracquisition of detailed synchronization and for detection of asynchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS. a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure. The embodiment of FIG. 7 may becombined with various embodiments of the present disclosure.

Referring to FIG. 7 , in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit an SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 8 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, (a) of FIG. 8 shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, (a) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example. (b) of FIG. 8 shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, (b) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 2.

Referring to (a) of FIG. 8 , in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (e.g., downlink control information (DCI)) or RRC signaling (e.g.,Configured Grant Type 1 or Configured Grant Type 2), and the UE 1 mayperform V2X or SL communication with respect to a UE 2 according to theresource scheduling. For example, the UE 1 may transmit a sidelinkcontrol information (SCI) to the UE 2 through a physical sidelinkcontrol channel (PSCCH), and thereafter transmit data based on the SCIto the UE 2 through a physical sidelink shared channel (PSSCH).

Referring to (b) of FIG. 8 , in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

Hereinafter, a sidelink control information (SCI) will be described.

Control information transmitted by a BS to a UE through a PDCCH may bereferred to as downlink control information (DCI), whereas controlinformation transmitted by the UE to another UE through a PSCCH may bereferred to as SCI. For example, the UE may know in advance a startsymbol of the PSCCH and/or the number of symbols of the PSCCH. beforedecoding the PSCCH. For example, the SCI may include SL schedulinginformation. For example, the UE may transmit at least one SCI toanother UE to schedule the PSSCH. For example, one or more SCI formatsmay be defined.

For example, a transmitting UE may transmit the SCI to a receiving UE onthe PSCCH. The receiving UE may decode one SCI to receive the PSSCH fromthe transmitting UE.

For example, the transmitting UE may transmit two consecutive SCIs(e.g.. 2-stage SCI) to the receiving UE on the PSCCH and/or the PSSCH.The receiving UE may decode the two consecutive SCIs (e.g., 2-stage SCI)to receive the PSSCH from the transmitting UE. For example, if SCIconfiguration fields are divided into two groups in consideration of a(relatively) high SCI payload size, an SCI including a first SCIconfiguration field group may be referred to as a first SCI or a 1^(st)SCI, and an SCI including a second SCI configuration field group may bereferred to as a second SCI or a 2^(nd) SCI. For example, thetransmitting UE may transmit the first SCI to the receiving UE throughthe PSCCH. For example, the transmitting UE may transmit the second SCIto the receiving UE on the PSCCH and/or the PSSCH. For example, thesecond SCI may be transmitted to the receiving UE through an(independent) PSCCH, or may be transmitted in a piggyback mannertogether with data through the PSSCH. For example, two consecutive SCIsmay also be applied to different transmissions (e.g., unicast,broadcast, or groupcast).

For example, the transmitting UE may transmit the entirety or part ofinformation described below to the receiving UE through the SCI. Herein,for example, the transmitting UE may transmit the entirety or part ofthe information described below to the receiving UE through the firstSCI and/or the second SCI.

-   PSSCH and/or PSCCH related resource allocation information, eg.. the    number/positions of time/frequency resources, resource reservation    information (e.g., period), and/or-   SL CSI report request indicator or SL (L1) RSRP (and/or SL (L1) RSRQ    and/or SL (L1) RSSI) report request indicator, and/or-   SL CSI transmission indicator (or SL (L1) RSRP (and/or SL (L1) RSRQ    and/or SL (L1) RSSI) information transmission indicator)) (on    PSSCH), and/or-   MCS information, and/or-   Transmit power information, and/or-   L1 destination ID information and/or L1 source ID information,    and/or-   SL HARQ process ID information, and/or-   New data indicator (NDI) information, and/or-   Redundancy version (RV) information, and/or-   (Transmission traffic/packet related) QoS information, e.g.,    priority information, and/or-   SL CSI-RS transmission indicator or information on the number of    (to-be-transmitted) SL CSI-RS antenna ports, and/or-   Location information of a transmitting UE or location (or distance    region) information of a target receiving UE (for which SL HARQ    feedback is requested), and/or-   Reference signal (e.g., DMRS, etc.) related to channel estimation    and/or decoding of data to be transmitted through a PSSCH, e.g.,    information related to a pattern of a (time-frequency) mapping    resource of DMRS, rank information, antenna port index information

For example, the first SCI may include information related to channelsensing. For example, the receiving UE may decode the second SCI byusing a PSSCH DMRS. A polar code used in a PDCCH may be applied to thesecond SCI. For example, in a resource pool, a payload size of the firstSCI may be identical for unicast, groupcast, and broadcast. Afterdecoding the first SCI. the receiving UE does not have to perform blinddecoding of the second SCI. For example, the first SCI may includescheduling information of the second SCI.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

In case of SL unicast and groupcast. HARQ feedback and HARQ combining inthe physical layer may be supported. For example, when a receiving UEoperates in a resource allocation mode 1 or 2, the receiving UE mayreceive the PSSCH from a transmitting UE, and the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE by using asidelink feedback control information (SFCI) format through a physicalsidelink feedback channel (PSFCH).

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

(1) Groupcast option 1: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of a transport block related to the PSCCH. the receiving UE maytransmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, ifthe receiving UE decodes the PSCCH of which the target is the receivingUE and if the receiving UE successfully decodes the transport blockrelated to the PSCCH, the receiving UE may not transmit the HARQ-ACK tothe transmitting UE.

(2) Groupcast option 2: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of the transport block related to the PSCCH, the receiving UEmay transmit HARQ-NACK to the transmitting UE through the PSFCH. Inaddition, if the receiving UE decodes the PSCCH of which the target isthe receiving UE and if the receiving UE successfully decodes thetransport block related to the PSCCH, the receiving UE may transmit theHARQ-ACK to the transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

For example, when the SL HARQ feedback is enabled for groupcast, thereceiving UE may determine whether to transmit the HARQ feedback to thetransmitting UE based on a transmission-reception (TX-RX) distanceand/or reference signal received power (RSRP).

For example, in the groupcast option 1, in case of the TX-RXdistance-based HARQ feedback, if the TX-RX distance is less than orequal to a communication range requirement, the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE. Otherwise,if the TX-RX distance is greater than the communication rangerequirement, the receiving UE may not transmit the HARQ feedback for thePSSCH to the transmitting UE. For example, the transmitting UE mayinform the receiving UE of a location of the transmitting UE through SCIrelated to the PSSCH. For example, the SCI related to the PSSCH may besecond SCI. For example, the receiving UE may estimate or obtain theTX-RX distance based on a location of the receiving UE and the locationof the transmitting UE. For example, the receiving UE may decode the SCIrelated to the PSSCH and thus may know the communication rangerequirement used in the PSSCH.

For example, in case of the resource allocation mode 1, a time (offset)between the PSFCH and the PSSCH may be configured or pre-configured. Incase of unicast and groupcast, if retransmission is necessary on SL,this may be indicated to a BS by an in-coverage UE which uses the PUCCH.The transmitting UE may transmit an indication to a serving BS of thetransmitting UE in a form of scheduling request (SR)/buffer statusreport (BSR), not a form of HARQ ACK/NACK. In addition, even if the BSdoes not receive the indication, the BS may schedule an SLretransmission resource to the UE. For example, in case of the resourceallocation mode 2, a time (offset) between the PSFCH and the PSSCH maybe configured or pre-configured.

For example, from a perspective of UE transmission in a carrier, TDMbetween the PSCCH/PSSCH and the PSFCH may be allowed for a PSFCH formatfor SL in a slot. For example, a sequence-based PSFCH format having asingle symbol may be supported. Herein, the single symbol may not an AGCduration. For example, the sequence-based PSFCH format may be applied tounicast and groupcast.

For example, in a slot related to a resource pool, a PSFCH resource maybe configured periodically as N slot durations, or may bepre-configured. For example, N may be configured as one or more valuesgreater than or equal to 1. For example, N may be 1, 2, or 4. Forexample, HARQ feedback for transmission in a specific resource pool maybe transmitted only through a PSFCH on the specific resource pool.

For example, if the transmitting UE transmits the PSSCH to the receivingUE across a slot #X to a slot #N, the receiving UE may transmit HARQfeedback for the PSSCH to the transmitting UE in a slot #(N+A). Forexample, the slot #(N+A) may include a PSFCH resource. Herein, forexample, A may be a smallest integer greater than or equal to K. Forexample, K may be the number of logical slots. In this case, K may bethe number of slots in a resource pool. Alternatively, for example, Kmay be the number of physical slots. In this case, K may be the numberof slots inside or outside the resource pool.

For example, if the receiving UE transmits HARQ feedback on a PSFCHresource in response to one PSSCH transmitted by the transmitting UE tothe receiving UE, the receiving UE may determine a frequency domainand/or code domain of the PSFCH resource based on an implicit mechanismin a configured resource pool. For example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of a slot index related to PSCCH/PSSCH/PSFCH, asub-channel related to PSCCH/PSSCH, and/or an identifier for identifyingeach receiving UE in a group for HARQ feedback based on the groupcastoption 2. Additionally/alternatively, for example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of SL RSRP, SINR, L1 source ID, and/or locationinformation.

For example, if HARQ feedback transmission through the PSFCH of the UEand HARQ feedback reception through the PSFCH overlap, the UE may selectany one of HARQ feedback transmission through the PSFCH and HARQfeedback reception through the PSFCH based on a priority rule. Forexample, the priority rule may be based on at least priority indicationof the related PSCCH/PSSCH.

For example, if HARQ feedback transmission of a UE through a PSFCH for aplurality of UEs overlaps, the UE may select specific HARQ feedbacktransmission based on the priority rule. For example, the priority rulemay be based on at least priority indication of the related PSCCH/PSSCH.

Hereinafter, SL radio link monitoring (RLM) will be described.

In case of AS-level link management of unicast, SL radio link monitoring(RLM) and/or radio link failure (RLF) declaration may be supported. Incase of RLC acknowledged mode (AM) in SL unicast, the RLF declarationmay be triggered by an indication from RLC indicating that the maximumnumber of retransmissions has been reached. An AS-level link status(e.g., failure) may need to be informed to a higher layer. Unlike theRLM procedure for unicast, a groupcast-related RLM design may not beconsidered. The RLM and/or RLF declarations may not be necessary betweengroup members for groupcast.

For example, a transmitting UE may transmit a reference signal to areceiving UE, and the receiving UE may perform SL RLM by using thereference signal. For example, the receiving UE may declare SL RLF byusing the reference signal. For example, the reference signal may bereferred to as an SL reference signal.

Hereinafter, SL measurement and reporting will be described.

For the purpose of QoS prediction, initial transmission parametersetting, link adaptation, link management, admission control, or thelike, SL measurement and reporting (e.g., RSRP, RSRQ) between UEs may beconsidered in SL. For example, a receiving UE may receive a referencesignal from a transmitting UE, and the receiving UE may measure achannel state for the transmitting UE based on the reference signal. Inaddition, the receiving UE may report channel state information (CSI) tothe transmitting UE. SL-related measurement and reporting may includemeasurement and reporting of CBR and reporting of location information.Examples of channel status information (CSI) for V2X may include achannel quality indicator (CQI), a precoding matrix index (PM), a rankindicator (RI), reference signal received power (RSRP), reference signalreceived quality (RSRQ), pathgain/pathloss, a sounding reference symbol(SRS) resource indicator (SRI), a SRI-RS resource indicator (CRI), aninterference condition, a vehicle motion, or the like. In case ofunicast communication, CQI, RI, and PMI or some of them may be supportedin a non-subband-based aperiodic CSI report under the assumption of fouror less antenna ports. A CSI procedure may not be dependent on astandalone reference signal (RS). A CSI report may be activated ordeactivated based on a configuration.

For example, the transmitting UE may transmit CSI-RS to the receivingUE, and the receiving UE may measure CQI or RI based on the CSI-RS. Forexample, the CSI-RS may be referred to as SL CSI-RS. For example, theCSI-RS may be confined within PSSCH transmission. For example, thetransmitting UE may perform transmission to the receiving UE byincluding the CSI-RS on the PSSCH.

Meanwhile, in the case of performing SL relay, a remote UE and a relayUE may find each other and set up a PC5 connection with each otherthrough PC5-signaling. For example, the remote UE and the relay UE mayset up a PC5-RRC connection. In this way, a state in which the PC5connection and/or the PC5-RRC connection is established between therelay UE and the remote UE may be defined as a linked state.

FIG. 9 shows an example of a relay scenario, based on an embodiment ofthe present disclosure. The embodiment of FIG. 9 may be combined withvarious embodiments of the present disclosure.

Meanwhile, the remote UE in a linked state and in an RRC_CONNECTED statemay transmit/receive data to/from the network through the relay UE. Inthis case, a problem of how to handle an unused Uu link of the remote UEmay occur. If the remote UE does not perform monitoring the Uu link inconsideration of power saving, the remote UE can obtain a gain for powersaving, but a latency may occur when switching from the PC5 link to theUu link. Due to the latency, service continuity performance maydeteriorate. In order to solve this problem, based on variousembodiments of the present disclosure, a method for efficientlyestablishing a Uu link by the UE and device(s) supporting the method areproposed.

Meanwhile, according to current operation, the remote UE may beconnected to one relay UE. If RLF occurs in a MAC layer or an RLC layerin a state where the PC5-RRC connection is established between theremote UE and the relay UE. the PC5-RRC connection may be releasedimmediately. In this case, the remote UE may have to find a new relay UEand set up a PC5 connection again, and latency may occur in the processof transmitting data to the network. In addition, even though the remoteUE has established a connection with one relay UE, additional power maybe consumed because new neighboring relay UEs should be searched. Inorder to solve this problem, based on various embodiments of the presentdisclosure, a method for the UE to perform communication through aplurality of relay UEs and device(s) supporting the same are proposed.

Based on an embodiment of the present disclosure, the remote UE and therelay UE may be in an RRC_CONNECTED state. For example, the relay UE andthe remote UE may be in a linked state in which a PC5 connection and/ora PC5-RRC connection is established with each other.

FIG. 10 shows a procedure for a remote UE to operate in a power savingmode, based on an embodiment of the present disclosure. The embodimentof FIG. 10 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 10 , in step S1000, the remote UE and the relay UE mayperform a discovery/connection setup procedure with each other, and mayenter a linked state as follows.

-   In a Prose layer, the remote UE and the relay UE may establish a PC5    connection, and/or-   In an RRC layer, the remote UE and the relay UE may establish a    PC5-RRC connection.

For example, the remote UE and the relay UE may be in an RRC_CONNECTEDstate with the network.

For example, if the remote UE and the relay UE are linked, and theremote UE transmits/receives data to/from the network through the relayUE, the network may know that the remote UE and the relay UE are linkedwith each other. For this, the remote UE or the relay UE may inform thenetwork of the linked state. In other words, if the remote UE and therelay UE are in a linked state, and the remote UE transmits/receivesdata to/from the network through the relay UE. the relay UE may transferor transmit information related to the linked state of the remote UE andthe relay UE to the network.

In step S1010, the remote UE in the linked state may perform thefollowing procedure for a Uu link. For example, the remote UE mayperform at least one of the following operations with respect to the Uulink in order to save power related to the Uu link. For example, theremote UE may perform different operations depending on a type of cellrelated to the Uu link.

For example, in the case of a PCell or a PUCCH secondary cell (SCell),long discontinuous reception (DRX) may be configured. For example, if acell related to the Uu link is a PCell or a PUCCH SCell, the remote UEmay configure DRX related to the Uu link to be long DRX. For example,the PUCCH SCell may be a SCell configured with PUCCH resource(s).

For example, in the case of a PCell or a PUCCH SCell, an initial BWP ora default BWP may be configured. For example, if a cell related to theUu link is a PCell or a PUCCH SCell, the remote UE may configure a BWPrelated to the Uu link to be an initial BWP or a default BWP.

For example, if the cell related to the Uu link is the PCell or thePUCCH SCell, the remote UE may configure DRX related to the Uu link tobe long DRX, and the remote UE may configure the BWP related to the Uulink to be the initial BWP or the default BWP.

For example, in case of a SCell, a DL BWP may be configured to be adormant BWP. For example, if a cell related to the Uu link is a SCell,the remote UE may configure a DL BWP to a dormant BWP. For example, thedormant BWP may be one of DL BWPs configured by the network throughdedicated RRC signaling. In the dormant BWP, the UE may stop monitoringa PDCCH for/on the SCell, but if configured, the UE may performcontinuously CSI measurement, automatic gain control (AGC), and beammanagement.

For example, the SCell may be deactivated. For example, if a cellrelated to the Uu link is a SCell, the remote UE may deactivate theSCell.

In step S1020, if the remote UE does not transmit or receive data withthe network, and the remote UE only perform PC5 transmission to therelay UE, the remote UE may release an RRC connection with the PCell andtransition to an RRC_IDLE state. For example, if the remote UE does nottransmit or receive data with the network, and the remote UE onlyperform PC5 transmission to the relay UE, the remote UE may suspend anRRC connection with the PCell and transition to an RRC_INACTIVE state.For example, if a data inactivity timer of the remote UE expires, theremote UE may release an RRC connection with the PCell and transition toan RRC_IDLE state. For example, if a data inactivity timer of the remoteUE expires, the remote UE may suspend an RRC connection with the PCelland transition to an RRC_INACTIVE state. For example, if the remote UEis unlikely to exchange data with the network, or if the data inactivitytimer of the remote UE expires, the remote UE may release an RRCconnection with the PCell and transition to an RRC_IDLE state, or theremote UE may suspend an RRC connection with the PCell and transition toan RRC_INACTIVE state.

Based on various embodiments of the present disclosure, the remote UElinked with the relay UE can save power related to Uu communication byadjusting BWP configurations, DRX configurations, etc. related to Uucommunication.

FIG. 11 shows a method for a remote UE to perform communication based ona plurality of relay UEs, based on an embodiment of the presentdisclosure. The embodiment of FIG. 11 may be combined with variousembodiments of the present disclosure.

For example, the remote UE may establish a PC5 connection and a PC5-RRCconnection with the relay UE and communicate with the network. Forexample, the remote UE may establish additional PC5 connections with newrelay UEs. Specifically, for example, if RSRP between the remote UE andthe relay UE is less than a specific threshold (configured or receivedthrough physical layer/higher layer signaling), the remote UE mayestablish additional PC5 connections with new relay UEs. For example,the number of (re)transmissions of the remote UE, which is not thenumber of retransmissions for SL RLF declaration, reaches a specificnumber (configured or received through physical layer/higher layersignaling) (e.g., which is less than the number for RLF declaration),the remote UE may establish additional PC5 connections with new relayUEs. For example, after the remote UE establishes a PC5 connection withone relay UE, the remote UE may establish additional PC5 connectionswith new relay UEs.

For example, the remote UE may preferentially select relay UEs inconsideration of the following. For example, the remote UE maypreferentially select a relay UE having the smallest number ofconnection hops to the network. For example, the remote UE maypreferentially select a relay UE having the same serving beam. Forexample, if relay UEs transmit discovery messages including beaminformation, the remote UE may preferentially select a relay UE havingthe same serving beam. For example, the remote UE may preferentiallyselect a relay UE belonging to the same serving cell as the remote UE.

For example, if the remote UE establishes PC5 and PC5-RRC connectionswith a plurality of relay UEs, the following procedure may be performed.In the present disclosure, an additionally connected relay UE may bereferred to as a redundant relay UE. However, the above names areexemplary, and other names indicating the additionally connected relayUE may be used. For example, a redundant relay UE may belong to the samecell as a relay UE connected with the remote UE. For example, aredundant relay UE may belong to a cell different from a relay UEconnected with the remote UE. For example, a redundant relay UE maybelong to a cell group different from a relay UE connected with theremote UE. For example, a PC5 and PC5-RRC connection may be establishedbetween connected relay UEs. For example, after discovering theredundant relay UE, the remote UE may perform the following operation.

- The remote UE may inform the connected relay UE of the redundant relayUE. For example, the remote UE may transmit information related to theredundant relay UE to the connected relay UE.

-   The remote UE may stop the procedure of discovering for additional    relay UEs.-   The remote UE may not perform PDCCH monitoring on the Uu link.-   The remote UE may not transmit scheduling request (SR)/buffer status    request (BSR) through the Uu link.-   If duplication transmission is activated, the remote UE may    simultaneously transmit the same MAC/RLC/PDCP PDU to the connected    relay UE and the redundant relay UE.-   If transmission based on carrier aggregation or dual connectivity is    configured, the remote UE may simultaneously transmit different    MAC/RLC/PDCP PDUs to the connected relay UE and redundant relay UE.

For example, the remote UE which transmits data through relay UE(s) mayknow that a problem has occurred with respect to a specific relay UE. Inthis case, the remote UE may suspend data being transmitted through therelay UE in which the problem has occurred. In addition, a relay path tothe network may be established through the connected redundant relay UE.An operation for this may be as follows.

-   The remote UE may initiate a procedure for discovering for    additional relay UEs.-   The remote UE may inform the network that a problem has occurred in    communication with the current relay UE, and the network may inform    the redundant relay UE that the relay path has been changed.-   The remote UE may inform the redundant relay UE that the relay path    has been changed and reset the relay path.-   (In case that a PC5 connection is established between relay UEs) the    remote UE may inform the current relay UE that a problem has    occurred, and the relay UE may notify the redundant relay UE that    the problem has occurred through the PC5 connection.

For example, the remote UE may reconfigure the redundant relay UE. Forexample, if a PC5 and PC5-RRC connection is established between relayUEs and SL quality is poor, the relay UEs may release the PC5 connectionbetween relay UEs, and the relay UEs may inform the remote UE of theconnection release, and the remote UE may release a connection with theconnected relay UE or the redundant relay UE. For example, the relay UEmay transmit a list of neighboring relay UEs to the remote UE based onthe measured value. For example, the relay UE may transmit a list ofneighboring relay UEs having a measurement result equal to or greaterthan a threshold (configured or received through physical layer/higherlayer signaling) to the remote UE. In this case, the remote UE maydiscover a new redundant relay UE by performing measurement for relayUEs in the list, and the remote UE may inform the connected relay UE ofthe newly discovered redundant relay UE.

Based on a method in which a remote UE is connected to only one relay UEas in the current method, if SL RLF occurs, the remote UE should searchfor another relay UE. On the other hand, based on a method in which aremote UE is connected to a plurality of relay UEs (e.g., redundantrelay UE) as in the method proposed in the present disclosure, if RLFoccurs with respect to one relay UE, the remote UE can relaycommunication with the network through the redundant relay UE to whichit is already connected. Through this, power consumption occurring in aprocess of additionally discovering a relay UE can be reduced. If theremote UE discovers the redundant relay UE, the remote UE may notperform a process of discovering a new relay UE, and the remote UE maynot perform PDCCH monitoring for the Uu link. Thus, additional powerconsumption can be reduced.

If duplication is configured, the remote UE can increase datareliability by transmitting the same PDU through both relay UEs. Ifcarrier aggregation or dual connectivity is configured, data throughputcan be improved.

Also, according to the prior art, if SL RLF occurs with respect to arelay UE, a latency may occur due to an operation of the remote UE tosearch for a new relay UE. On the other hand, according to variousembodiments of the present disclosure, since the remote UE canimmediately perform a relay UE reselection procedure based on theredundant relay UE (without a process of discovering a relay UE), it ispossible to reduce latency required to discover and newly configure arelay UE.

FIG. 12 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure. The embodimentof FIG. 12 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 12 , in step S1210, the first device may establish aradio resource control (RRC) connection with a base station. In stepS1220, the first device may establish a PC5 connection with a seconddevice relaying communication between the first device and the basestation. In step S1230, the first device may configure a power savingmode for saving power related to Uu communication between the basestation and the first device, based on the establishment of the PC5connection with the second device. In step S1240, the first device mayperform communication with the base station based on the power savingmode.

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: configuring discontinuous reception (DRX) related to theUu communication as long DRX, based on that a cell related to the Uucommunication is a primary cell (PCell).

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: configuring discontinuous reception (DRX) related to theUu communication as long DRX, based on that a cell related to the Uucommunication is a secondary cell (SCell) for which a physical uplinkcontrol channel (PUCCH) resource is configured.

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: configuring a bandwidth part (BWP) on a primary cell(PCell) as an initial BWP or a default BWP, based on that a cell relatedto the Uu communication is the PCell.

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: configuring a bandwidth part (BWP) on a secondary cell(SCell) as an initial BWP or a default BWP, based on that a cell relatedto the Uu communication is the SCell for which a physical uplink controlchannel (PUCCH) resource is configured.

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: configuring a downlink (DL) bandwidth part (BWP) on asecondary cell (SCell) as a dormant BWP, based on that a cell related tothe Uu communication is the SCell. For example, monitoring of a physicaldownlink control channel (PDCCH) by the first device on the dormant BWPmay be stopped.

For example, configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicemay comprise: deactivating a secondary cell (SCell) based on that a cellrelated to the Uu communication is the SCell.

Additionally, for example, the first device may release the RRCconnection based on that the Uu communication is not performed on aprimary cell (PCell) during a time duration configured for the firstdevice. In this case, for example, an RRC state between the first deviceand the base station may transition from an RRC_CONNECTED state to anRRC_IDLE state.

Additionally, for example, the first device may suspend the RRCconnection based on that the Uu communication is not performed on aprimary cell (PCell) during a time duration configured for the firstdevice. In this case, for example, an RRC state between the first deviceand the base station may transition from an RRC_CONNECTED state to anRRC INACTIVE state.

Additionally, for example, the first device may release the RRCconnection based on an expiration of a data inactivity timer configuredfor the first device. In this case, for example, an RRC state betweenthe first device and the base station may transition from anRRC_CONNECTED state to an RRC_IDLE state.

For example, the communication with the base station may be performedthrough the second device.

Additionally, for example, the first device may transmit, to the basestation, information representing that the PC5 connection is establishedbetween the first device and the second device.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 102 of thefirst device 100 may establish a radio resource control (RRC) connectionwith a base station. In addition, the processor 102 of the first device100 may establish a PC5 connection with a second device relayingcommunication between the first device and the base station. Inaddition, the processor 102 of the first device 100 may configure apower saving mode for saving power related to Uu communication betweenthe base station and the first device, based on the establishment of thePC5 connection with the second device. In addition, the processor 102 ofthe first device 100 may control the transceiver 106 to performcommunication with the base station based on the power saving mode.

Based on an embodiment of the present disclosure, a first device adaptedto perform wireless communication may be provided. For example, thefirst device may comprise: one or more memories storing instructions;one or more transceivers; and one or more processors connected to theone or more memories and the one or more transceivers. For example, theone or more processors may execute the instructions to: establish aradio resource control (RRC) connection with a base station; establish aPC5 connection with a second device relaying communication between thefirst device and the base station; configure a power saving mode forsaving power related to Uu communication between the base station andthe first device, based on the establishment of the PC5 connection withthe second device; and perform communication with the base station basedon the power saving mode.

Based on an embodiment of the present disclosure, an apparatus adaptedto control a first user equipment (UE) may be provided. For example, theapparatus may comprise: one or more processors; and one or more memoriesoperably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: establish a radio resource control (RRC) connectionwith a base station: establish a PC5 connection with a second UErelaying communication between the first UE and the base station;configure a power saving mode for saving power related to Uucommunication between the base station and the first UE, based on theestablishment of the PC5 connection with the second UE; and performcommunication with the base station based on the power saving mode.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: establish a radio resource control (RRC) connection with a basestation; establish a PC5 connection with a second device relayingcommunication between the first device and the base station; configure apower saving mode for saving power related to Uu communication betweenthe base station and the first device, based on the establishment of thePC5 connection with the second device; and perform communication withthe base station based on the power saving mode.

FIG. 13 shows a method for performing wireless communication by a basestation, based on an embodiment of the present disclosure. Theembodiment of FIG. 13 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 13 , in step S1310, the base station may establish afirst radio resource control (RRC) connection with a first device. Instep S1320, the base station may establish a second RRC connection witha second device. In step S1330, the base station may performcommunication with the first device, based on a power saving mode forsaving power related to Uu communication between the base station andthe first device. For example, the second device may be a device forrelaying communication between the first device and the base station,and based on that a PC5 connection is established between the firstdevice and the second device, the power saving mode may be configuredfor the first device.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 202 of thebase station 200 may establish a first radio resource control (RRC)connection with a first device. In addition, the processor 202 of thebase station 200 may establish a second RRC connection with a seconddevice. In addition, the processor 202 of the base station 200 maycontrol the transceiver 206 to perform communication with the firstdevice, based on a power saving mode for saving power related to Uucommunication between the base station and the first device. Forexample, the second device may be a device for relaying communicationbetween the first device and the base station, and based on that a PC5connection is established between the first device and the seconddevice, the power saving mode may be configured for the first device.

Based on an embodiment of the present disclosure, a base station adaptedto perform wireless communication may be provided. For example, the basestation may comprise: one or more memories storing instructions; one ormore transceivers: and one or more processors connected to the one ormore memories and the one or more transceivers. For example, the one ormore processors may execute the instructions to: establish a first radioresource control (RRC) connection with a first device; establish asecond RRC connection with a second device; and perform communicationwith the first device, based on a power saving mode for saving powerrelated to Uu communication between the base station and the firstdevice. For example, the second device may be a device for relayingcommunication between the first device and the base station, and basedon that a PC5 connection is established between the first device and thesecond device, the power saving mode may be configured for the firstdevice.

Based on an embodiment of the present disclosure, an apparatusconfigured to control a base station may be provided. For example, theapparatus may comprise: one or more processors: and one or more memoriesoperably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: establish a first radio resource control (RRC)connection with a first user equipment (UE); establish a second RRCconnection with a second UE; and perform communication with the firstUE. based on a power saving mode for saving power related to Uucommunication between the base station and the first UE. For example,the second UE may be a UE for relaying communication between the firstUE and the base station, and based on that a PC5 connection isestablished between the first UE and the second UE, the power savingmode may be configured for the first UE.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a base stationto: establish a first radio resource control (RRC) connection with afirst device: establish a second RRC connection with a second device:and perform communication with the first device, based on a power savingmode for saving power related to Uu communication between the basestation and the first device. For example, the second device may be adevice for relaying communication between the first device and the basestation, and based on that a PC5 connection is established between thefirst device and the second device, the power saving mode may beconfigured for the first device.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 14 shows a communication system 1, based on an embodiment of thepresent disclosure.

Referring to FIG. 14 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices. Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an extended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (Al) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1. and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300. thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g.. 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay. Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 15 shows wireless devices, based on an embodiment of the presentdisclosure.

Referring to FIG. 15 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 14 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208 The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs. SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202 The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 16 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

Referring to FIG. 16 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 16 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 15 . Hardwareelements of FIG. 16 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 15 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 15. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 15 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 15 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 16 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 16 . For example, the wireless devices(e.g., 100 and 200 of FIG. 15 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 17 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 14 ).

Referring to FIG. 17 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 15 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 15 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 15 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g.. other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 14 ), the vehicles (100 b-1 and 100 b-2 of FIG. 14 ), the XRdevice (100 c of FIG. 14 ), the hand-held device (100 d of FIG. 14 ),the home appliance (100 e of FIG. 14 ), the IoT device (100 f of FIG. 14), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 14 ), the BSs (200 of FIG. 14 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 17 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 17 will be described indetail with reference to the drawings.

FIG. 18 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT).

Referring to FIG. 18 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 17 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g.. touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 19 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc.

Referring to FIG. 19 , a vehicle or autonomous vehicle 100 may includean antenna unit 108. a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 17 , respectively.

The communication unit 110 may transmit and receive signals (e.g.. dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is: 1-20. (canceled)
 21. A method for performingwireless communication by a first device, the method comprising:establishing a radio resource control (RRC) connection with a basestation; establishing a PC5 connection with a second device relayingcommunication between the first device and the base station; configuringa power saving mode for saving power related to Uu communication betweenthe base station and the first device, based on the establishment of thePC5 connection with the second device; and performing communication withthe base station based on the power saving mode.
 22. The method of claim21, wherein configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicecomprises: configuring discontinuous reception (DRX) related to the Uucommunication as long DRX, based on that a cell related to the Uucommunication is a primary cell (PCell).
 23. The method of claim 21,wherein configuring the power saving mode for saving power related tothe Uu communication between the base station and the first devicecomprises: configuring discontinuous reception (DRX) related to the Uucommunication as long DRX, based on that a cell related to the Uucommunication is a secondary cell (SCell) for which a physical uplinkcontrol channel (PUCCH) resource is configured.
 24. The method of claim21, wherein configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicecomprises: configuring a bandwidth part (BWP) on a primary cell (PCell)as an initial BWP or a default BWP, based on that a cell related to theUu communication is the PCell.
 25. The method of claim 21, whereinconfiguring the power saving mode for saving power related to the Uucommunication between the base station and the first device comprises:configuring a bandwidth part (BWP) on a secondary cell (SCell) as aninitial BWP or a default BWP, based on that a cell related to the Uucommunication is the SCell for which a physical uplink control channel(PUCCH) resource is configured.
 26. The method of claim 21, whereinconfiguring the power saving mode for saving power related to the Uucommunication between the base station and the first device comprises:configuring a downlink (DL) bandwidth part (BWP) on a secondary cell(SCell) as a dormant BWP, based on that a cell related to the Uucommunication is the SCell.
 27. The method of claim 26, whereinmonitoring of a physical downlink control channel (PDCCH) by the firstdevice on the dormant BWP is stopped.
 28. The method of claim 21,wherein configuring the power saving mode for saving power related tothe Uu communication between the base station and the first devicecomprises: deactivating a secondary cell (SCell) based on that a cellrelated to the Uu communication is the SCell.
 29. The method of claim21, further comprising: releasing the RRC connection based on that theUu communication is not performed on a primary cell (PCell) during atime duration configured for the first device, wherein an RRC statebetween the first device and the base station transitions from anRRC_CONNECTED state to an RRC IDLE state.
 30. The method of claim 21,further comprising: suspending the RRC connection based on that the Uucommunication is not performed on a primary cell (PCell) during a timeduration configured for the first device, wherein an RRC state betweenthe first device and the base station transitions from anRRC_(_)CONNECTED state to an RRC INACTIVE state.
 31. The method of claim21, further comprising: releasing the RRC connection based on anexpiration of a data inactivity timer configured for the first device,wherein an RRC state between the first device and the base stationtransitions from an RRC_(_)CONNECTED state to an RRC IDLE state.
 32. Themethod of claim 21, wherein the communication with the base station isperformed through the second device.
 33. The method of claim 21, furthercomprising: transmitting, to the base station, information representingthat the PC5 connection is established between the first device and thesecond device.
 34. A first device adapted to perform wirelesscommunication, the first device comprising: one or more transceivers;one or more processors operably connected to the one or moretransceivers; and one or more memories operably connected to the one ormore processors and storing instructions that, when executed by the oneor more processors, perform operations comprising: establishing a radioresource control (RRC) connection with a base station; establishing aPC5 connection with a second device relaying communication between thefirst device and the base station; configuring a power saving mode forsaving power related to Uu communication between the base station andthe first device, based on the establishment of the PC5 connection withthe second device; and performing communication with the base stationbased on the power saving mode.
 35. The first device of claim 34,wherein configuring the power saving mode for saving power related tothe Uu communication between the base station and the first devicecomprises: configuring discontinuous reception (DRX) related to the Uucommunication as long DRX, based on that a cell related to the Uucommunication is a primary cell (PCell).
 36. The first device of claim34, wherein configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicecomprises: configuring discontinuous reception (DRX) related to the Uucommunication as long DRX, based on that a cell related to the Uucommunication is a secondary cell (SCell) for which a physical uplinkcontrol channel (PUCCH) resource is configured.
 37. The first device ofclaim 34, wherein configuring the power saving mode for saving powerrelated to the Uu communication between the base station and the firstdevice comprises: configuring a bandwidth part (BWP) on a primary cell(PCell) as an initial BWP or a default BWP, based on that a cell relatedto the Uu communication is the PCell.
 38. The first device of claim 34,wherein configuring the power saving mode for saving power related tothe Uu communication between the base station and the first devicecomprises: configuring a bandwidth part (BWP) on a secondary cell(SCell) as an initial BWP or a default BWP, based on that a cell relatedto the Uu communication is the SCell for which a physical uplink controlchannel (PUCCH) resource is configured.
 39. The first device of claim34, wherein configuring the power saving mode for saving power relatedto the Uu communication between the base station and the first devicecomprises: configuring a downlink (DL) bandwidth part (BWP) on asecondary cell (SCell) as a dormant BWP, based on that a cell related tothe Uu communication is the SCell.
 40. A processing device adapted tocontrol a first device, the processing device comprising: one or moreprocessors; and one or more memories operably connected to the one ormore processors and storing instructions that, when executed by the oneor more processors, perform operations comprising: establishing a radioresource control (RRC) connection with a base station; establishing aPC5 connection with a second device relaying communication between thefirst device and the base station; configuring a power saving mode forsaving power related to Uu communication between the base station andthe first device, based on the establishment of the PC5 connection withthe second device; and performing communication with the base stationbased on the power saving mode.